The present invention relates to a cooling technique and an information processing apparatus and particularly to a technique effectively adapted to a technique for cooling a space-saving type personal computer, or the like.
For example, with the advance of semiconductor techniques or the like, performance of a microprocessor used in a personal computer or the like has been improved remarkably. Particularly, a product with an operating frequency of the level of GHz has been used widely.
On the other hand, with the users"" requirement for space saving and with reduction in cost of a liquid-crystal display, a so-called notebook type portable personal computer which has a liquid-crystal display and a body foldably connected to each other by a hinge has come into wide use. Moreover, an integral display type desktop personal computer which has a personal computer body integrated with the back or lower portion of a liquid-crystal display has come into wide use.
When a high-performance microprocessor with the level of GHz is mounted in such a space-saving type personal computer to provide the personal computer as a product, one of technical problems is means how to cool the microprocessor (to radiate heat from the microprocessor).
It is heretofore known that a cooling fan is disposed near the microprocessor or in a part of a housing so that the cooling fan forcedly generates an air stream passing through the microprocessor portion to radiate heat.
In the air-cooling system using such a fan, however, heat radiation has become insufficient because a large amount of heat is sent out when the existing high-speed microprocessor with the level of GHz is in operation. If heat radiation is to be made forcedly, a large-sized fan is required. There arises another technical problem in increase of the fan size and the housing size, increase of power consumption, increase of noise, or the like.
In such a space-saving type personal computer, small size, low noise, low power consumption, etc. are important selling points. Hence, increase in size of the housing, increase in power consumption and increase in noise as described above is a large technical problem against producing a space-saving type personal computer.
Therefore, it has been conceived that a liquid-cooling type cooling system using liquid as a thermal medium to thereby make it possible to achieve a large cooling capacity is employed. In this case, it is necessary to use a pump to circulate the liquid thermal medium between a heat-generating portion such as a microprocessor and a heat-radiating portion such as a radiator. In such a pump, however, the flow rate is generally controlled by the frequency or magnitude applied to the pump. Hence, there was a technical problem that a complex circuit such as a frequency control circuit or a voltage control circuit was required for controlling the flow rate of the thermal medium delicately.
On the other hand, the heat-radiating portion of the microprocessor, or the like, has a predetermined heat capacity. Hence, if cooling owing to the thermal medium is stopped immediately after the system is stopped, the temperature of the heat-radiating portion for the microprocessor, or the like, rises up rapidly because of residual heat. Hence, there was fear that the heat-radiating portion of the microprocessor, or the like, might be damaged by heat stress, etc.
An object of the present invention is to provide a technique in which reduction in size, noise and power consumption can be achieved in an information processing apparatus such as a space-saving type personal computer and, at the same time, high performance can be achieved by use of a microprocessor with a high operating frequency.
Another object of the present invention is to provide an information processing apparatus such as a space-saving type personal computer having a liquid-cooling type cooling system in which simplification of the configuration and control of a system for circulating a thermal medium is achieved.
A further object of the present invention is to provide an information processing apparatus such as a space-saving type personal computer having a liquid-cooling type cooling system in which failure is prevented from being caused by residual heat after the apparatus stops.
According to an aspect of the present invention, in an information processing apparatus having an information processing portion and an information display portion which are integrated with each other, there is provided a cooling method for cooling a heat-generating portion of the information processing apparatus by circulating a thermal medium between a cooling jacket mounted on a heat-generating portion and a heat-radiating portion to thereby cool the heat-generating portion, in which the circulation of the cooling liquid is continued until the temperature of the heat-generating portion becomes not higher than a predetermined value even after the information processing apparatus is stopped.
According to another aspect of the present invention, in an information processing apparatus having an information processing portion and an information display portion which are integrated with each other, there is provided a cooling method for cooling a heat-generating portion of the information processing apparatus by circulating a thermal medium between a cooling jacket mounted on a heat-generating portion and a heat-radiating portion to thereby cool the heat-generating portion, in which the length of at least one of an applied period of operating electric power and a stop period of the operating electric power is controlled under a predetermined voltage or under a predetermined frequency to thereby control the flow rate when a pump for circulating the cooling medium has such a characteristic that the flow rate increases in proportion to the voltage or frequency of operating electric power given from the outside.